const { Service } = require('egg');

const sha256 = require("crypto-js/sha256");

const CryptoJS = require("crypto-js");

const KEY = CryptoJS.enc.Utf8.parse('BDQH');

class BaseService extends Service {
    shaForm = (body, salt) => {
        return sha256(sha256(body).toString() + salt).toString();
    }

    encryptRequest = (body) => {
        return CryptoJS.AES.encrypt(body, KEY, {
            mode: CryptoJS.mode.ECB,
            padding: CryptoJS.pad.Pkcs7
        }).toString();
    }

    decryptRequest = (body) => {
        return CryptoJS.AES.decrypt(body, KEY, {
            mode: CryptoJS.mode.ECB,
            padding: CryptoJS.pad.Pkcs7
        }).toString(CryptoJS.enc.Utf8);
    }

    // 随机盐生成函数
    generateRandomString = () => {
        const lowerCaseLetters = 'abcdefghijklmnopqrstuvwxyz';
        const upperCaseLetters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
        const numbers = '0123456789';

        let result = '';

        // 生成5位随机小写字母
        for (let i = 0; i < 5; i++) {
            const randomIndex = Math.floor(Math.random() * lowerCaseLetters.length);
            result += lowerCaseLetters[randomIndex];
        }

        // 生成5位随机大写字母
        for (let i = 0; i < 5; i++) {
            const randomIndex = Math.floor(Math.random() * upperCaseLetters.length);
            result += upperCaseLetters[randomIndex];
        }

        // 生成2位随机数字
        for (let i = 0; i < 2; i++) {
            const randomIndex = Math.floor(Math.random() * numbers.length);
            result += numbers[randomIndex];
        }

        // 打乱整个字符串
        const characters = result.split('');
        for (let i = characters.length - 1; i > 0; i--) {
            const j = Math.floor(Math.random() * (i + 1));
            [characters[i], characters[j]] = [characters[j], characters[i]];
        }

        return characters.join('');
    }

    // 教学接口 token 验证，验证 token 是否存在，是否在黑名单中
    Verify = async (redis, teachingToken) => {
        const token = await redis.get('db4').get(teachingToken);
        if (!token) {
            return 401;
        } else if (JSON.parse(token).attacksMark) {
            return 403;
        }
        return JSON.parse(token).uid;
    }

    shunt = (uid) => {
        return uid[uid.length - 1];
    }

    isAllDigits = (str) => {
        const regex = /^\d+$/;
        return regex.test(str);
    }
}

module.exports = BaseService;